sweet gum vs gum

sweet gum and gum both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweet gum	Yes	No	No	No
gum	Yes	No	Yes	No

As nouns, gum is a hypernym of sweet gum; that is, gum is a word with a broader meaning than sweet gum:

sweet gum: aromatic exudate from the sweet gum tree
gum: any of various substances (soluble in water) that exude from certain plants; they are gelatinous when moist but harden on drying

As nouns, gum is a hypernym of sweet gum; that is, gum is a word with a broader meaning than sweet gum:

sweet gum: reddish-brown wood and lumber from heartwood of the sweet gum tree used to make furniture
gum: wood or lumber from any of various gum trees especially the sweet gum

Other hypernyms of sweet gum include gumwood.

sweet gum (noun)	gum (noun)
a North American tree of the genus Liquidambar having prickly spherical fruit clusters and fragrant sap	the tissue (covered by mucous membrane) of the jaws that surrounds the bases of the teeth
aromatic exudate from the sweet gum tree	a preparation (usually made of sweetened chicle) for chewing
reddish-brown wood and lumber from heartwood of the sweet gum tree used to make furniture	any of various trees of the genera Eucalyptus or Liquidambar or Nyssa that are sources of gum
	wood or lumber from any of various gum trees especially the sweet gum
	any of various substances (soluble in water) that exude from certain plants; they are gelatinous when moist but harden on drying
	cement consisting of a sticky substance that is used as an adhesive

sweet gum (verb)	gum (verb)
	exude or form gum
	become sticky
	grind with the gums; chew without teeth and with great difficulty
	cover, fill, fix or smear with or as if with gum